[linux.git] / fs / jffs2 / TODO


 - support asynchronous operation -- add a per-fs 'reserved_space' count,
   let each outstanding write reserve the _maximum_ amount of physical
   space it could take. Let GC flush the outstanding writes because the
   reservations will necessarily be pessimistic. With this we could even
   do shared writable mmap, if we can have a fs hook for do_wp_page() to
   make the reservation.
 - disable compression in commit_write()?
 - fine-tune the allocation / GC thresholds
 - chattr support - turning on/off and tuning compression per-inode
 - checkpointing (do we need this? scan is quite fast)
 - make the scan code populate real inodes so read_inode just after 
	mount doesn't have to read the flash twice for large files.
	Make this a per-inode option, changeable with chattr, so you can
	decide which inodes should be in-core immediately after mount.
 - test, test, test

 - NAND flash support:
	- almost done :)
	- use bad block check instead of the hardwired byte check

 - Optimisations:
   - Split writes so they go to two separate blocks rather than just c->nextblock.
	By writing _new_ nodes to one block, and garbage-collected REF_PRISTINE
	nodes to a different one, we can separate clean nodes from those which
	are likely to become dirty, and end up with blocks which are each far
	closer to 100% or 0% clean, hence speeding up later GC progress dramatically.
   - Stop keeping name in-core with struct jffs2_full_dirent. If we keep the hash in 
     the full dirent, we only need to go to the flash in lookup() when we think we've
     got a match, and in readdir(). 
   - Doubly-linked next_in_ino list to allow us to free obsoleted raw_node_refs immediately?
   - Remove size from jffs2_raw_node_frag. 

dedekind:
1. __jffs2_flush_wbuf() has a strange 'pad' parameter. Eliminate.
2. get_sb()->build_fs()->scan() path... Why get_sb() removes scan()'s crap in
   case of failure? scan() does not clean everything. Fix.
Commit	Line	Data
1da177e4	1
733802d9 AB	2	- support asynchronous operation -- add a per-fs 'reserved_space' count,
	3	let each outstanding write reserve the _maximum_ amount of physical
	4	space it could take. Let GC flush the outstanding writes because the
	5	reservations will necessarily be pessimistic. With this we could even
	6	do shared writable mmap, if we can have a fs hook for do_wp_page() to
	7	make the reservation.
1da177e4 LT	8	- disable compression in commit_write()?
	9	- fine-tune the allocation / GC thresholds
	10	- chattr support - turning on/off and tuning compression per-inode
	11	- checkpointing (do we need this? scan is quite fast)
	12	- make the scan code populate real inodes so read_inode just after
	13	mount doesn't have to read the flash twice for large files.
25985edc	14	Make this a per-inode option, changeable with chattr, so you can
1da177e4 LT	15	decide which inodes should be in-core immediately after mount.
	16	- test, test, test
	17
	18	- NAND flash support:
733802d9 AB	19	- almost done :)
733802d9 AB	20	- use bad block check instead of the hardwired byte check
1da177e4 LT	21
1da177e4 LT	22	- Optimisations:
733802d9 AB	23	- Split writes so they go to two separate blocks rather than just c->nextblock.
	24	By writing _new_ nodes to one block, and garbage-collected REF_PRISTINE
	25	nodes to a different one, we can separate clean nodes from those which
	26	are likely to become dirty, and end up with blocks which are each far
	27	closer to 100% or 0% clean, hence speeding up later GC progress dramatically.
1da177e4 LT	28	- Stop keeping name in-core with struct jffs2_full_dirent. If we keep the hash in
	29	the full dirent, we only need to go to the flash in lookup() when we think we've
	30	got a match, and in readdir().
	31	- Doubly-linked next_in_ino list to allow us to free obsoleted raw_node_refs immediately?
1da177e4	32	- Remove size from jffs2_raw_node_frag.
733802d9 AB	33
	34	dedekind:
	35	1. __jffs2_flush_wbuf() has a strange 'pad' parameter. Eliminate.
	36	2. get_sb()->build_fs()->scan() path... Why get_sb() removes scan()'s crap in
	37	case of failure? scan() does not clean everything. Fix.